Touch-sensitive surfaces are rapidly becoming more common in computing devices. They are very convenient as they allow a user to make natural gestures familiar to the user in other contexts, such as by entering handwriting using a stylus. Many of these devices also allow input to be provided by non-stylus objects, such as a user's fingertip. The term touch-sensitive surface or device will be used herein to refer to such surfaces or devices that are configured to detect the touch of a stylus and/or a non-stylus object. While generally a convenient feature, a disadvantage to this dual sensitivity to both a stylus and a non-stylus object such as the user's finger is that it is likely that the user will, from time to time, unintentionally touch the touch-sensitive surface with the user's finger, hand, etc., while handling the device or writing on the device using a stylus. For example, while using the stylus to write, the user may rest his or her hand on the touch-sensitive surface, and/or brush the hand against the surface. This may also happen while the user is holding or otherwise handling the device.
There is therefore a need to address this problem inherent to touch-sensitive devices sensitive to both stylus-based input and non-stylus-based input.